Lignocellulosic Composite Articles

ABSTRACT

A lignocellulosic composite article includes a plurality of lignocellulosic pieces and an adhesive system disposed on the plurality of lignocellulosic pieces for bonding the plurality of lignocellulosic pieces. The adhesive system includes a binder component and a compatibilizer component. An example of a suitable binder component is an isocyanate component, e.g. a diphenylmethane diisocyanate (MDI), a polymeric diphenylmethane diisocyanate (pMDI), and combinations thereof. The compatibilizer component includes a trialkyl phosphate. The compatibilizer component is utilized in an amount of at least about 0.5 parts by weight based on 100 parts by weight of the binder component. The compatibilizer component is useful for reducing the amount of press time required during manufacture of the composite article. The adhesive system can include additional components, such as an isocyanate-reactive component. The composite article may be various lignocellulosic composites, such as oriented strand board (OSB), particleboard (PB), fiberboard (e.g. medium density fiberboard; MDF), etc.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and all the advantages of U.S.Provisional Patent Application Ser. Nos. 61/884,223 and 62/032,123,filed on Sep. 30, 2013 and Aug. 1, 2014, respectively, the contents ofeach of which are expressly incorporated herein by reference in one ormore non-limiting embodiments.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to lignocellulosic compositearticles, and more specifically, to lignocellulosic composite articlesincluding a plurality of lignocellulosic pieces and an adhesive systemdisposed on the plurality of lignocellulosic pieces, and to methods offorming the lignocellulosic composite articles.

DESCRIPTION OF THE RELATED ART

Lignocellulosic composite articles, such as oriented strand board (OSB),oriented strand lumber (OSL), particleboard (PB), scrimber, agrifiberboard, chipboard, flakeboard, and fiberboard, e.g. medium densityfiberboard (MDF), are generally produced by blending or sprayinglignocellulosic pieces with a binder composition, e.g. a resin, whilethe lignocellulosic pieces are tumbled or agitated in a blender orsimilar apparatus. After blending sufficiently to form abinder-lignocellulosic mixture, the lignocellulosic pieces, which arenow coated with the binder composition, are formed into a product,specifically a loose mat, which is compressed between heatedplatens/plates to set the binder composition and to bond thelignocellulosic pieces together in densified form, such as in a board,panel, or other shape. Conventional processes for compressing the loosemat are generally carried out at temperatures of from about 120° C. toabout 225° C., in the presence of varying amounts of steam, eitherpurposefully injected into the loose mat or generated by liberation ofentrained moisture from the lignocellulosic pieces in the loose mat.These processes also generally require that the moisture content of thelignocellulosic pieces be between about 2% and about 20% by weight,before blending the lignocellulosic pieces with the binder composition.

The lignocellulosic pieces can be in the form of chips, shavings,strands, scrim, wafers, fibers, sawdust, bagasse, straw and wood wool.When the lignocellulosic pieces are relatively larger in size, e.g. from1 to 7 inches, the lignocellulosic composite articles produced by theprocess can be called engineered wood. These engineered woods includelaminated strand lumber, OSB, OSL, scrimber, parallel strand lumber, andlaminated veneer lumber. When the lignocellulosic pieces are relativelysmaller, e.g. typical sawdust and refined fiber sizes, thelignocellulosic composite articles are particleboard (PB) andfiberboard, e.g. MDF. Other engineered woods, such as plywood, employlarger sheets of lumber, which are held together by a binder compositionin a sandwich configuration. Yet other engineered woods, such asscrimber, employ thin, long, irregular pieces of wood having averagediameters ranging from about 2 to 10 mm and lengths several feet inlength.

The engineered woods were developed because of the increasing scarcityof suitably sized tree trunks for cutting lumber. Such engineered woodscan have advantageous physical properties such as strength andstability. Another advantage of the engineered woods is that they can bemade from the waste material generated by processing other wood andlignocellulosic materials. This leads to efficiencies and energy savingsfrom the recycling process, and saves landfill space.

Binder compositions that have been used for making such lignocellulosiccomposite articles include phenol formaldehyde (PF) resins, ureaformaldehyde (UF) resins and isocyanate resins. Binder compositionsbased on isocyanate chemistry are commercially desirable because theyhave low water absorption, high adhesive and cohesive strength,flexibility in formulation, versatility with respect to cure temperatureand rate, excellent structural properties, the ability to bond withlignocellulosic materials having high water contents, and importantly,zero formaldehyde emissions. Lignocellulosic composite articlesutilizing such binder compositions are imparted with correspondingproperties/benefits.

Lignocellulosic materials can be treated with polymethylene poly(phenylisocyanates) (also known as polymeric MDI or pMDI) to improve thestrength of the composite article. Typically, such treatment involvesapplying the isocyanate to the lignocellulosic material and allowing theisocyanate to cure, either by application of heat and pressure or atroom temperature. While it is possible to allow the pMDI to cure underambient conditions, residual isocyanate (NCO) groups remain on thetreated articles for weeks or even months in some instances. Toluenediisocyanate (TDI) can also be utilized for such purposes, but isgenerally less acceptable from an environmental standpoint. Isocyanateprepolymers are among the preferred isocyanate materials that have beenused in binder compositions to solve various processing problems,particularly, in reducing adhesion to press platens and for reducingreactivity of the isocyanates.

Unfortunately, disadvantages of using isocyanates in place of PF and/orUF resins include difficulty in processing due to adhesion to platens,lack of tack or cold-tack (i.e., the isocyanates are not “tacky” or“sticky”), and the need for special storage in certain scenarios. Inaddition, isocyanates can also have extended cure times, which reducesmanufacturing output of composite articles utilizing the same. Further,some isocyanates and related components can have too high ofviscosities, which impairs handling of the same, and increases cost ofmanufacture of composite articles utilizing such components.

Accordingly, there remains an opportunity to provide improved adhesivesystems useful for forming lignocellulosic composite articles. Therealso remains an opportunity to provide improved lignocellulosiccomposite articles and improved methods of forming such lignocellulosiccomposite articles.

SUMMARY OF THE DISCLOSURE AND ADVANTAGES

A lignocellulosic composite article (“the article”) includes a pluralityof lignocellulosic pieces and an adhesive system disposed on theplurality of lignocellulosic pieces for bonding the plurality oflignocellulosic pieces. The adhesive system includes a binder componentand a compatibilizer component. In certain embodiments, the bindercomponent includes an isocyanate component. The compatibilizer componentincludes a trialkyl phosphate (TAP). The compatibilizer component isutilized in an amount of at least about 0.5 parts by weight based on 100parts by weight of the binder component. A method of forming the articleincludes the step of applying the binder component and thecompatibilizer component to the plurality of lignocellulosic pieces. Themethod further includes the step of disposing the plurality oflignocellulosic pieces having the binder component and thecompatibilizer component applied thereon on a carrier to form a mass.The method further includes the step of applying pressure and/or heat tothe mass for an amount of time sufficient to form the article.

Without being bound or limited to any particular theory, it is thoughtthat presence of the compatibilizer component reduces the amount of timerequired to form the article relative to the amount of time requiredwhen the compatibilizer component is not utilized to form the article.Specifically, it is thought that the compatibilizer component is usefulfor reducing cure time of the adhesive system during manufacture of thearticle. As such, throughput of the articles can be increased viaincreased manufacturing speeds, e.g. press speeds (i.e., shorterpressing times). Other manufacturing benefits can also be realized, suchas improved application of the components of the adhesive system to theplurality of lignocellulosic pieces relative to conventional adhesives.In addition, it is believed that the disclosure articles includeexcellent physical properties. For example, in certain embodiments, thearticles can have one or more of the following: increased bond strength,reduced edge swelling, improved release properties, improved flexuralmodulus, and/or reduced emissions, each relative to conventionalarticles. It is thought that other potential advantages afforded by theuse of the compatibilizer component are: improved plasticization of thelignocellulosic pieces; reduced binder component viscosity leading toimproved distribution on the lignocellulosic pieces; and improved flametest performance of the articles. It is thought that the compatibilizercomponent can also improve the performance of other, optional,components utilized to form the articles, such as polyols through phasetransfer catalysis and/or viscosity reducing mechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present disclosure will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawing(s) wherein:

FIG. 1 is an interval plot illustrating density of lignocellulosiccomposite articles described in the Examples section;

FIG. 2 is an interval plot illustrating thickness (inches) oflignocellulosic composite articles described in the Examples section;

FIG. 3 is a plot illustrating internal bond (IB) strength (psi) andpress time (seconds) of lignocellulosic composite articles described inthe Examples section;

FIG. 4 is a plot illustrating density adjusted IB strength (psi) andpress time (seconds) of lignocellulosic composite articles described inthe Examples section;

FIG. 5 is a plot illustrating IB strength (psi) and press time (seconds)of lignocellulosic composite articles described in the Examples section;

FIG. 6A is a line graph showing water contact angle of the first,second, and third samples on stainless steel measured in tenths ofseconds;

FIG. 6B is a photograph of a droplet of deionized water on stainlesssteel showing water contact angle;

FIG. 6C is a photograph of a droplet of a mixture of deionized water anda silicone surfactant on stainless steel showing water contact angle;

FIG. 6D is a photograph of a droplet of a mixture of deionized water, asilicone surfactant, and TEP, on stainless steel showing water contactangle;

FIG. 7A is a line graph showing water contact angle of the first,second, and third samples on steel measured in tenths of seconds;

FIG. 7B is a photograph of a droplet of deionized water on steel showingwater contact angle;

FIG. 7C is a photograph of a droplet of a mixture of deionized water anda silicone surfactant on steel showing water contact angle;

FIG. 7D is a photograph of a droplet of a mixture of deionized water, asilicone surfactant, and TEP, on steel showing water contact angle;

FIG. 8A is a line graph showing water contact angle of the first,second, and third samples on aluminum measured in tenths of seconds;

FIG. 8B is a photograph of a droplet of deionized water on aluminumshowing water contact angle;

FIG. 8C is a photograph of a droplet of a mixture of deionized water anda silicone surfactant on aluminum showing water contact angle; and

FIG. 8D is a photograph of a droplet of a mixture of deionized water, asilicone surfactant, and TEP, on aluminum showing water contact angle.

DETAILED DESCRIPTION OF THE DISCLOSURE

A lignocellulosic composite article (the “article”) is disclosed herein.The article can be used for various applications. Examples of suchapplications include, but are not limited to, for packaging; forfurniture and cabinetry; for roof and floor sheathing; for roof, floor,and siding paneling; for window and door frames; and for webstock, e.g.webstock for engineered I-beams.

The article, in various embodiments, can be referred to as various formsof engineered lignocellulosic composites, e.g., as engineered woodcomposites, such as oriented strand board (OSB); oriented strand lumber(OSL); scrimber; fiberboard, such as low density fiberboard (LDF),medium density fiberboard (MDF), and high density fiberboard (HDF);chipboard; flakeboard or flake board; particleboard (PB); plywood; etc.Generally, the article is in the form OSB, OSL, PB, scrimber, plywood,LDF, MDF, or HDF, more typically in the form of PB, MDF, HDF, or OSB;however, it is to be appreciated that the article may be in otherengineered wood forms, such as, but not limited to, those described andexemplified herein. It is to be appreciated that the names oflignocellulosic composite articles are often used interchangeably in theart. For example, one may refer to a composite as OSB whereas anothermay refer to the same composite as flake board.

The article includes a plurality of lignocellulosic pieces. Thelignocellulosic pieces can be derived from a variety of lignocellulosicmaterials. Generally, the lignocellulosic pieces are derived from wood;however, the lignocellulosic pieces can be derived from otherlignocellulosic materials, such as from bagasse, straw, flax residue,nut shells, cereal grain hulls, etc., and mixtures thereof. If wood isutilized as the lignocellulosic material, the lignocellulosic pieces canbe prepared from various species of hardwoods and/or softwoods.Non-lignocellulosic materials in flake, fibrous or other particulateform, such as glass fiber, mica, asbestos, rubber, plastics, etc., canalso be mixed with the lignocellulosic material; however, such materialsare not generally required.

The lignocellulosic pieces can come from a variety of processes, such asby comminuting small logs, industrial wood residue, branches, roughpulpwood, etc. into pieces in the form of sawdust, chips, flakes, wafer,strands, scrim, fibers, sheets, etc. In certain embodiments, thelignocellulosic pieces include those pieces typically utilized forforming OSB, OSL, scrimber, and particleboards (PB). In otherembodiments, the lignocellulosic pieces include those pieces typicallyutilized for forming fiberboards, such as LDF, MDF, and HDF. In yetanother embodiment the lignocellulosic pieces include those piecestypically utilized for forming plywood. It is to be appreciated that thearticle can include various combinations of the aforementioned materialsand/or pieces, such as strands and sawdust. In addition, the article maybe formed into shapes other than panels and boards.

The lignocellulosic pieces can be produced by various conventionaltechniques. For example, pulpwood grade logs can be converted intoflakes in one operation with a conventional roundwood flaker.Alternatively, logs and logging residue can be cut into fingerlings onthe order of from about 0.5 to about 3.5 inches long with a conventionalapparatus, and the fingerlings flaked in a conventional ring typeflaker. The logs are typically debarked before flaking. The article isnot limited to any particular method of forming the lignocellulosicpieces.

The dimensions of the lignocellulosic pieces are not particularlycritical. In certain embodiments, such as those used to form OSB, thelignocellulosic pieces typically include strands having an averagelength of from about 2.5 to about 6 inches, an average width of fromabout 0.5 to about 2 inches, and an average thickness of from about 0.1to about 0.5 inches. It is to be appreciated that other sizes can alsobe utilized, as desired by one skilled in the art. In some of theseembodiments, the article may include other types of lignocellulosicpieces, such as chips, in addition to the strands. In certainembodiments, strands which are typically about 1.5 inches wide and about12 inches long can be used to make laminated strand lumber, whilestrands typically about 0.12 inches wide and about 9.8 inches long canbe used to make parallel strand lumber. In certain embodiments, such asthose used to form flakeboard, the lignocellulosic pieces include flakeshaving an average length of from about 2 to about 6 inches, an averagewidth of about 0.25 to about 3 inches, and an average thickness of fromabout 0.005 to about 0.05 inches. In other embodiments, such as thoseused to from scrimber, the lignocellulosic pieces include thin,irregular pieces having average diameters ranging from about 0.25 toabout 20, about 0.5 to about 15, or about 1 to about 10, mm, and lengthsranging from several inches to several feet in length. Detailedinformation on suitable sizes and shapes of lignocellulosic pieces,e.g., scrim, as well as methods of manufacturing scrimber, is describedin U.S. Pat. No. 6,344,165 to Coleman, the disclosure of which isincorporated herein by reference in its entirety. In yet otherembodiments, the lignocellulosic pieces are those typically used to formconventional PB. The lignocellulosic pieces can be further milled priorto use, if such is desired to produce a size more suitable for producinga desired article. For example, hammer, wing beater, and toothed diskmills may be used for forming lignocellulosic pieces of various sizesand shapes.

The lignocellulosic pieces can have various moisture contents, where ifpresent, water can serve as an isocyanate-reactive component, which isdescribed further below. Typically, the lignocellulosic pieces have amoisture content of from about 1 to about 20, about 2 to about 15, about3 to about 12, or about 5 to about 10, parts by weight (water), based on100 parts by weight of the lignocellulosic pieces, or any subrange inbetween. If present in (and/or on) the lignocellulosic pieces, the waterassists in the curing or setting of the article. It is to be appreciatedthat the lignocellulosic pieces can have inherent moisture content; oralternatively, water may be added to or removed from the lignocellulosicpieces, such as by wetting or drying the lignocellulosic pieces,respectively, to obtain a desired moisture content of thelignocellulosic pieces prior to and/or during formation of the article.

The lignocellulosic pieces are utilized in the article in variousamounts, depending on the type of article desired to be formed.Typically, such as in OSB, PB, scrimber, or MDF applications, thelignocellulosic pieces are utilized in an amount of from about 75 toabout 99, about 85 to about 98, about 90 to about 97, or about 92 toabout 95.5, parts by weight, based on 100 parts by weight of thearticle, or any subrange in between. It is to be appreciated that theamounts can be higher or lower depending on various factors, includingmoisture content of the lignocellulosic pieces. For example, moisturecontent of the lignocellulosic pieces can vary by geographic location,source, etc., such as variations from mill to mill.

The article further includes an adhesive system. In certain embodiments,the article includes the lignocellulosic pieces and the adhesive system.In further embodiments, the article consists essentially of thelignocellulosic pieces and the adhesive system. In yet furtherembodiments, the article consists of the lignocellulosic pieces and theadhesive system. In other related embodiments, the article furtherincludes an additive component.

The adhesive system is disposed on the lignocellulosic pieces forbonding the lignocellulosic pieces. By “disposed on”, it is meant thatthe adhesive system is in contact with at least a portion of thelignocellulosic pieces. The adhesive system includes a binder componentand a compatibilizer component. The adhesive system may include one ormore additional components, as described below. The adhesive isgenerally formed from the binder component and the compatibilizercomponent. It is to be appreciated that in many embodiments, the bindercomponent reacts (e.g. with water, itself, and/or another component),such that it may only exist for a period of time during formation of thearticle. For example, most to all of the binder component may be reactedduring formation of the article such that little to no binder componentremains in the article after formation. In other embodiments, someamount of the binder component may be present in the article afterformation.

The binder component is typically chosen from an isocyanate component, aformaldehyde resin, a protein-based adhesive, or a combination thereof.If utilized, the isocyanate component is typically a polymericdiphenylmethane diisocyanate (pMDI); however, other isocyanates can alsobe utilized as described below. If utilized, the formaldehyde resin istypically a urea formaldehyde (UF) resin or a melamine UF resin,however, other formaldehydes can also be used, e.g. a phenolformaldehyde (PF) resin. If utilized, the protein-based adhesive istypically a soy-based adhesive, however, other protein-based adhesivescan also be utilized, e.g. a casein-based adhesive.

In general, the binder component is only present for some amount of timeprior to a reaction product thereof curing to a final cured state toform the adhesive system, and therefore, the article. In other words,the reaction product is generally the final cured state of the adhesivesystem, after reaction occurs between the components used to form thearticle, e.g. after reaction between the isocyanate component and anisocyanate-reactive component (described below).

Components of the adhesive can be premixed or combined to form theadhesive system and then the adhesive system can be applied to thelignocellulosic pieces. In certain embodiments, the binder component,the compatibilizer component, and optionally, one or more additionalcomponents, are individually applied to the lignocellulosic pieces,and/or already present thereon, during formation of the article, ratherthen being premixed and applied, all of which is further describedbelow. In other embodiments, two or more of the components are premixedand applied, e.g. the binder and compatibilizer components, thecompatibilizer and isocyanate-reactive components, etc.

The binder component generally adheres the lignocellulosic pieces to oneanother, once cured. For example, the reaction product of the isocyanatecomponent and the isocyanate-reactive component can bond thelignocellulosic pieces via linkages, e.g. urea linkages. Thecompatibilizer component is generally inert such that it is not part ofthe reaction product (albeit it may be present therein). Generalmechanisms of adhesion, for wood composites, are detailed in pages 397through 399 of THE POLYURETHANES HANDBOOK (David Randall & Steve Leeeds., John Wiley & Sons, Ltd. 2002), the disclosure of which isincorporated herein by reference in its entirety in various non-limitingembodiments.

In a first embodiment of the binder component, the adhesive systemincludes the reaction product of the isocyanate component and theisocyanate-reactive component reactive with the isocyanate component.The isocyanate component is typically a polyisocyanate having two ormore functional groups, e.g. two or more isocyanate (NCO) groups. Saidanother way, the isocyanate component can just be an isocyanate or acombination of isocyanates. Suitable organic polyisocyanates include,but are not limited to, conventional aliphatic, cycloaliphatic,araliphatic and aromatic isocyanates. In certain embodiments, theisocyanate component is chosen from diphenylmethane diisocyanates(MDIs), polymeric diphenylmethane diisocyanates (pMDIs), andcombinations thereof. Polymeric diphenylmethane diisocyanates can alsobe called polymethylene polyphenylene polyisocyanates. In otherembodiments, the isocyanate component is an emulsifiable MDI (eMDI).Examples of other suitable isocyanates include, but are not limited to,toluene diisocyanates (TDIs), hexamethylene diisocyanates (HDIs),isophorone diisocyanates (IPDIs), naphthalene diisocyanates (NDIs), andcombinations thereof. In a specific embodiment, the isocyanate componentis MDI. In another specific embodiment, the isocyanate component ispMDI. In further specific embodiments, the isocyanate component is acombination of MDI and pMDI.

In certain embodiments, the isocyanate component is anisocyanate-terminated prepolymer. The isocyanate-terminated prepolymeris a reaction product of an isocyanate and a polyol and/or a polyamine.The isocyanate may be any type of isocyanate in the polyurethane art,such as one of the polyisocyanates. If utilized to make theisocyanate-terminated prepolymer, the polyol is typically chosen fromethylene glycol, diethylene glycol, propylene glycol, dipropyleneglycol, butane diol, glycerol, trimethylolpropane, triethanolamine,pentaerythritol, sorbitol, and combinations thereof. The polyol may alsobe a polyol as described and exemplified further below with discussionof the isocyanate-reactive component. If utilized to make theisocyanate-terminated prepolymer, the polyamine is typically chosen fromethylene diamine, toluene diamine, diaminodiphenylmethane andpolymethylene polyphenylene polyamines, aminoalcohols, and combinationsthereof. Examples of suitable aminoalcohols include ethanolamine,diethanolamine, triethanolamine, and combinations thereof. Theisocyanate-terminated prepolymer may be formed from a combination of twoor more of the aforementioned polyols and/or polyamines.

The isocyanates or isocyanate-terminated prepolymers may also be used inthe form of an aqueous emulsion by mixing such materials with water inthe presence of an emulsifying agent. The isocyanate component may alsobe a modified isocyanate, such as, carbodiimides, allophanates,isocyanurates, and biurets.

Other suitable isocyanates include those described in U.S. Pat. No.4,742,113 to Gismondi et al.; U.S. Pat. No. 5,093,412 to Mente et al.;U.S. Pat. No. 5,425,976 to Clarke et al.; U.S. Pat. No. 6,297,313 toHsu; U.S. Pat. No. 6,352,661 to Thompson et al.; U.S. Pat. No. 6,451,101to Mente et al.; U.S. Pat. No. 6,458,238 to Mente et al.; U.S. Pat. No.6,464,820 to Mente et al.; U.S. Pat. No. 6,638,459 to Mente et al.; U.S.Pat. No. 6,649,098 to Mente et al.; U.S. Pat. No. 6,822,042 to Capps;U.S. Pat. No. 6,846,849 to Capps; U.S. Pat. No. 7,422,787 to Evers etal.; U.S. Pat. No. 7,439,280 to Lu et al.; and U.S. Pat. No. 8,486,523to Mente; and U.S. Publication No. 2005/0242459 to Savino et al.; thedisclosures of which are incorporated herein by reference in theirentirety in various non-limiting embodiments.

Specific examples of suitable isocyanate components are commerciallyavailable from BASF Corporation of Florham Park, N.J., under thetrademark LUPRANATE®, such as LUPRANATE® M, LUPRANATE® M20, LUPRANATE®MI, LUPRANATE® M20SB, LUPRANATE® M20HB, and LUPRANATE® M20FBisocyanates. In one embodiment, the isocyanate component is LUPRANATE®M20. In another embodiment, the isocyanate component is LUPRANATE®M20FB. It is to be appreciated that the isocyanate component may includeany combination of the aforementioned isocyanates and/orisocyanate-terminated prepolymers.

If utilized, the isocyanate component typically has a viscosity which issuitable for specific applications of the isocyanate component to thelignocellulosic pieces, such as by spraying, fogging and/or atomizingthe isocyanate component to apply the isocyanate component to thelignocellulosic pieces. Typically, the isocyanate component has aviscosity of from about 100 to about 5,000, about 100 to about 2,500, orabout 100 to about 1,000, cps at 25° C. according to ASTM D2196, or anysubrange in between. Regardless of the application technique, theviscosity of the isocyanate component should be sufficient to adequatelycoat the lignocellulosic pieces.

The adhesive system can include the reaction product of the isocyanatecomponent and the isocyanate-reactive component. In one embodiment, theisocyanate-reactive component is water, which may be applied to and/oralready present on the lignocellulosic pieces, e.g. as a preexistingmoisture content (or a portion thereof). In other embodiments, theisocyanate-reactive component includes a polyol and/or a polyamine. Incertain embodiments, the isocyanate-reactive component includes apolymer polyol, which may also be referred to as a graft polyol. Theisocyanate-reactive component can include a combination of theaforementioned isocyanate-reactive components, e.g. water and a polyol.

Typically, such as in OSB, PB, scrimber, or MDF applications, theisocyanate-reactive component is utilized in an amount of from about 1to about 20, about 1 to about 15, or about 2 to about 10, parts byweight, based on 100 parts by weight of lignocellulosic pieces, or anysubrange in between. The amounts described herein are generally based onthe assumption that the lignocellulosic pieces are completely dry toaccount for variations in moisture contents of the lignocellulosicpieces. More specific amounts are described below. If water is utilizedat the isocyanate-reactive component, it can be present in these amountsor in the amounts regarding moisture content of the lignocellulosicpieces.

If utilized, the polyol is typically chosen from conventional polyols,such as ethylene glycol, diethylene glycol, propylene glycol,dipropylene glycol, butane diol, glycerol, trimethylolpropane,triethanolamine, pentaerythritol, sorbitol, and combinations thereof.Other suitable polyols include, but are not limited to, biopolyols, suchas soybean oil, castor-oil, soy-protein, rapeseed oil, etc., andcombinations thereof. It is believed that certain polyols impartplasticization and/or film formation, and tackiness, which may increasewith pressure. For example, some polyols may act as a plasticizer,especially in conjunction with the compatibilizer component.

Suitable polyether polyols include, but are not limited to, productsobtained by the polymerization of a cyclic oxide, for example ethyleneoxide (EO), propylene oxide (PO), butylene oxide (BO), ortetrahydrofuran in the presence of polyfunctional initiators. Suitableinitiator compounds contain a plurality of active hydrogen atoms, andinclude water, butanediol, ethylene glycol, propylene glycol (PG),diethylene glycol, triethylene glycol, dipropylene glycol, ethanolamine,diethanolamine, triethanolamine, toluene diamine, diethyl toluenediamine, phenyl diamine, diphenylmethane diamine, ethylene diamine,cyclohexane diamine, cyclohexane dimethanol, resorcinol, bisphenol A,glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, andcombinations thereof.

Other suitable polyether polyols include polyether diols and triols,such as polyoxypropylene diols and triols andpoly(oxyethylene-oxypropylene)diols and triols obtained by thesimultaneous or sequential addition of ethylene and propylene oxides todi- or trifunctional initiators. Copolymers having oxyethylene contentsof from about 5 to about 90% by weight, based on the weight of thepolyol component, of which the polyols may be block copolymers,random/block copolymers or random copolymers, can also be used. Yetother suitable polyether polyols include polytetramethylene glycolsobtained by the polymerization of tetrahydrofuran.

Suitable polyester polyols include, but are not limited to,hydroxyl-terminated reaction products of polyhydric alcohols, such asethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol,neopentylglycol, 1,6-hexanediol, cyclohexane dimethanol, glycerol,trimethylolpropane, pentaerythritol or polyether polyols or mixtures ofsuch polyhydric alcohols, and polycarboxylic acids, especiallydicarboxylic acids or their ester-forming derivatives, for examplesuccinic, glutaric and adipic acids or their dimethyl esters sebacicacid, phthalic anhydride, tetrachlorophthalic anhydride or dimethylterephthalate or mixtures thereof. Polyester polyols obtained by thepolymerization of lactones, e.g. caprolactone, in conjunction with apolyol, or of hydroxy carboxylic acids, e.g. hydroxy caproic acid, mayalso be used.

Suitable polyesteramides polyols may be obtained by the inclusion ofaminoalcohols such as ethanolamine in polyesterification mixtures.Suitable polythioether polyols include products obtained by condensingthiodiglycol either alone or with other glycols, alkylene oxides,dicarboxylic acids, formaldehyde, aminoalcohols or aminocarboxylicacids. Suitable polycarbonate polyols include products obtained byreacting diols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol,diethylene glycol or tetraethylene glycol with diaryl carbonates, e.g.diphenyl carbonate, or with phosgene. Suitable polyacetal polyolsinclude those prepared by reacting glycols such as diethylene glycol,triethylene glycol or hexanediol with formaldehyde. Other suitablepolyacetal polyols may also be prepared by polymerizing cyclic acetals.Suitable polyolefin polyols include hydroxy-terminated butadiene homo-and copolymers and suitable polysiloxane polyols includepolydimethylsiloxane diols and triols.

Specific examples of suitable polyols are commercially available fromBASF Corporation under the trademark of PLURACOL®. It is to beappreciated that the isocyanate-reactive component may include anycombination of two or more of the aforementioned polyols.

In certain embodiments utilizing the polymer polyol, the polymer polyolis a graft polyol. Graft polyols may also be referred to as graftdispersion polyols or graft polymer polyols. Graft polyols often includeproducts, i.e., polymeric particles, obtained by the in-situpolymerization of one or more vinyl monomers, e.g. styrene monomersand/or acrylonitrile monomers, and a macromer in a polyol, e.g. apolyether polyol. In one embodiment, the isocyanate-reactive componentis a styrene-acrylonitrile (SAN) graft polyol.

In other embodiments, the polymer polyol is chosen from polyharnstoff(PHD) polyols, polyisocyanate polyaddition (PIPA) polyols, andcombinations thereof. It is to be appreciated that theisocyanate-reactive component can include any combination of theaforementioned polymer polyols. PHD polyols are typically formed byin-situ reaction of a diisocyanate with a diamine in a polyol to give astable dispersion of polyurea particles. PIPA polyols are similar to PHDpolyols, except that the dispersion is typically formed by in-situreaction of a diisocyanate with an alkanoamine instead of a diamine, togive a polyurethane dispersion in a polyol. The article is not limitedto any particular method of making the polymer polyol.

If utilized, the polymer polyol can serve as a sizing agent substitute,e.g. a sizing wax or wax sizing agent substitute, specifically byimparting a certain degree of water repellency to the article, onceformed. Paraffin, for example, is a common wax sizing agent for OSB andOSL applications. In certain embodiments, the article is substantiallyfree of a wax component, such as paraffin. By “substantially free”, itis meant that in these embodiments, the wax component is typicallypresent in an amount no greater than about 5, no greater than about 2.5,no greater than about 1.5, or approaching or equaling 0, parts byweight, based on 100 parts by weight of the lignocellulosic pieces, orany subrange in between. In certain embodiments, the article iscompletely free of a wax component.

One method by which the polymer polyol can impart water repellency is byat least partially coating a surface of the lignocellulosic pieces, thusdecreasing surface tension of the surface. Another method by which thepolymer polyol imparts water repellency is that the polymer polyol atleast partially fills capillaries within and between the lignocellulosicpieces, thus providing a barrier to capillary uptake of water. Further,it is believed that the polymer polyol reduces formation of micro-and/or nano-cracks from forming within the article, for example, withinthe adhesive, during or after cure to form the reaction product. Yetfurther, if such cracks are already present in the lignocellulosicpieces, the polymer polyol at least partially fills such cracks, as withdescription of the capillaries. It is believed that the blocking ofwater and filling of cracks reduces de-lamination and swelling problemswhen the article is exposed to moisture during use. It is furtherbelieved that such “filling” largely occurs due to the polymericparticles of the polymer polyol.

In various embodiments, the polymer polyol includes a continuous phaseand a discontinuous phase. The continuous phase of the polymer polyol isnot generally miscible with the isocyanate component, which provides forincreased coverage of the polymeric particles with reactive groups, suchas hydroxyl (OH) groups. Such reactive groups can further impartcrosslinking in the article, once the reactive groups are reacted. Thepolymeric particles are further described below.

In certain embodiments, the polyol of the polymer polyol is ahydrophobic polyol. In a specific embodiment, the polyol is ahydrophobic polyether polyol. In another specific embodiment, the polyolis a hydrophobic polyester polyol. The hydrophobic polyol containsalkylene oxides. In these embodiments, the hydrophobic polyol typicallyhas from about 0 to about 50, about 2 to about 20, or about 5 to about15, parts by weight of ethylene oxide (EO), based on 100 parts by weightof the alkylene oxides of the hydrophobic polyol, or any subrange inbetween. In other embodiments, the hydrophobic polyol typically has atleast 60, at least 70, or at least 80, parts by weight propylene oxide(PO), based on 100 parts by weight of the alkylene oxides, or anysubrange in between. Accordingly, in these embodiments, the hydrophobicpolyol is a propylene oxide rich polyol, which imparts the hydrophobicpolyol with hydrophobicity, and therefore further imparts the articlewith hydrophobicity.

In certain embodiments, the alkylene oxides of the hydrophobic polyolinclude a mixture of EO and PO. In another embodiment, the alkyleneoxides of the hydrophobic polyol include only PO, i.e., the hydrophobicpolyol does not include other alkylene oxides, such as EO. In certainembodiments, the hydrophobic polyol includes other types of alkyleneoxides known in the art, e.g. butylene oxide (BO), in combination withPO, and optionally, in combination with EO. The alkylene oxides of thehydrophobic polyol may be arranged in various configurations, such as arandom (heteric) configuration, a block configuration, a cappedconfiguration, or a combination thereof. For example, in one embodiment,the hydrophobic polyol includes a heteric mixture of EO and PO.

In certain embodiments, the hydrophobic polyol is terminally capped withEO. The hydrophobic polyol typically has a terminal cap of from about 5to about 25, about 5 to about 20, or about 10 to about 15, parts byweight EO, based on 100 parts by weight of the hydrophobic polyol, orany subrange in between. In certain embodiments, the EO may only bepresent in the terminal ethylene oxide cap; however, in otherembodiments, the EO may also be present along with the PO, andoptionally, with other alkylene oxides, e.g. BO, in the alkylene oxidesof the hydrophobic polyol. Generally, it is thought that increasing thePO content of the hydrophobic polyol is preferred in order to impartincreased hydrophobicity to the article.

Suitable hydrophobic polyols include, but are not limited to,glycerine-initiated, trimethylolpropane-initiated, propyleneglycol-initiated, and sucrose-initiated polyether polyols, andcombinations thereof. In one embodiment, the hydrophobic polyol is aglycerine-initiated polyether polyol. The alkylene oxides of thehydrophobic polyol generally extend from the respective initiatorportion of the hydrophobic polyol.

The discontinuous phase of the graft polyol includes polymericparticles. If micro- and/or nano-cracks are present in thelignocellulosic pieces, it is believed that the polymeric particles ofthe discontinuous phase of the polymer polyol at least partially fillthese cracks. The polymeric particles are generally large in size due totheir macromer constituents, i.e., the polymeric particles havemicrometer or larger dimensions, e.g. micrometer or larger diameters. Incertain embodiments, the polymeric particles have average diametersranging from about 0.1 to about 10 microns, alternatively from about 0.1to about 1.5 microns, or any subrange in between. In other embodiments,the polymeric particles have average diameters less than 0.1 microns,which imparts the polymer polyol with nano-polymeric particles. Blockingof water and filling of cracks reduces de-lamination and swellingproblems when the article is exposed to moisture during storage or use.In addition to filling cracks, in certain embodiments, the polymericparticles are reactive with the isocyanate component, which may increaseinternal bond (IB) strength of the article. The polymeric particlestypically include the reaction product of monomers chosen from styrenes,e.g. alpha-methyl styrene, acrylonitriles, esters of acrylic andmethacrylic acids, ethylenic ally unsaturated nitriles, amines, amides,and combinations thereof. In certain embodiments, the polymericparticles include the further reaction of a macromer, such as a polyolhaving an unsaturation, which permits chemical incorporation of thepolymeric particle. In these embodiments, it is believed that thepolymeric particles can impart crosslinking in the article, due toreactive groups attached to the polymeric particles, e.g. OH groups,which can react with the isocyanate component. It is also believed thatthe polymeric particles can serve as a “hot melt” adhesive depending ontheir specific chemical makeup, e.g. polymeric particles formed fromstyrene and acrylonitrile monomers.

In one embodiment, the polymeric particles include styrene acrylonitrile(SAN) copolymers, which are the reaction product of styrene monomers andacrylonitrile monomers. Typically, the SAN copolymers have a weightratio of styrene to acrylonitrile of from about 30:70 to about 70:30,about 40:60 to about 60:40, about 45:55 to about 60:40, about 50:50 toabout 60:40, or about 55:45 to about 60:40, or any subrange in between.In one embodiment, the SAN copolymers have a weight ratio of styrene toacrylonitrile of about 66.7:33.3. In another embodiment, the polymericparticles are urea, which are the reaction product of an amine monomerand an isocyanate (NCO) group, such as an NCO group of a diisocyanate.In yet another embodiment, the polymeric particles are urethane, whichare the reaction product of an alcohol monomer and an isocyanate (NCO)group, such as an NCO group of a diisocyanate.

Typically, the polymeric particles are present in the polymer polyol inan amount of from about 5 to about 70, about 15 to about 55, or about 25to about 50, parts by weight, based on 100 parts by weight of thepolymer polyol, or any subrange in between. In one embodiment, thepolymeric particles are present in the polymer polyol in an amount ofabout 65 parts by weight based on 100 parts by weight of the graftpolyol. Generally, increasing the amount of polymeric particlesincreases the water repellency of the article.

The polymer polyol typically has a molecular weight of from about 400 toabout 20,000, about 500 to about 10,000, about 600 to about 5,000, orabout 700 to about 3,000, or any subrange in between. In one embodiment,the polymer polyol has a molecular weight of about 730. In anotherembodiment, the polymer polyol has a molecular weight of about 3,000.

Other suitable polymer polyols and methods of making the same includethose described in U.S. Pat. No. 4,522,976 to Grace et al.; U.S. Pat.No. 5,093,412 to Mente et al.; U.S. Pat. No. 5,179,131 to Wujcik et al.;U.S. Pat. No. 5,223,570 to Huang et al.; U.S. Pat. No. 5,594,066 toHeinemann et al.; U.S. Pat. No. 5,814,699 to Kratz et al.; U.S. Pat. No.6,034,146 to Falke et al.; U.S. Pat. No. 6,103,140 to Falke et al.; U.S.Pat. No. 6,352,658 to Chang et al.; U.S. Pat. No. 6,432,543 to Harrisonet al.; U.S. Pat. No. 6,472,447 to Lorenz et al.; U.S. Pat. No.6,649,107 to Harrison et al.; and U.S. Pat. No. 7,179,882 to Adkins etal., the disclosures of which are incorporated herein by reference invarious non-limiting embodiments.

Specific examples of suitable polymer polyols are commercially availablefrom BASF Corporation, under the trademark PLURACOL®, such as PLURACOL®1365, PLURACOL® 4600, PLURACOL® 4650, PLURACOL® 4800, PLURACOL® 4815,PLURACOL® 4830, and PLURACOL® 4850 graft polyols. In a specificembodiment, the isocyanate-reactive component includes PLURACOL® 4650.In another embodiment, the isocyanate-reactive component is PLURACOL®2086 and/or PLURACOL® 593. The isocyanate-reactive component may includeany combination of the aforementioned polymer polyols. Detailedinformation on polymer polyols is described on pages 104 and 105 of THEPOLYURETHANES HANDBOOK (David Randall & Steve Lee eds., John Wiley &Sons, Ltd. 2002), which are incorporated herein in their entirety invarious non-limiting embodiments.

If utilized, the polymer polyol typically has a viscosity which issuitable for specific applications of the polymer polyol to thelignocellulosic pieces, such as by spraying, fogging and/or atomizingthe polymer polyol to apply the polymer polyol to the lignocellulosicpieces. Typically, the polymer polyol has a viscosity of from about 100to about 10,000, about 500 to about 5,000, or about 500 to about 3,000,cps at 25° C. according to ASTM D2196, or any subrange in between.Regardless of application technique, the viscosity of the polymer polyolshould be sufficient to adequately coat the lignocellulosic pieces.

If utilized, the polymer polyol is typically utilized in an amount offrom about 5 to about 40, about 10 to about 30, or about 15 to about 25,parts by weight, based on 100 parts by weight of the adhesive system, orany subrange in between. The isocyanate-reactive component may includeany combination of the aforementioned polyols, polymeric particles,and/or types of polymer polyols.

The adhesive system may further include an auxiliary polyol, differentthan the polyol in the polymer polyol, if the isocyanate component isutilized as the binder component. Suitable polyols for use as theauxiliary polyol are as described with the isocyanate-terminatedprepolymer. The auxiliary polyol can be used for various purposes. Forexample, an auxiliary polyol having a higher functionality (relative tothe polyol of the polymer polyol) can be utilized to provide additionalreactive groups for reaction with the isocyanate component, or anauxiliary polyol can be utilized to increase or decrease viscosity ofthe adhesive system. The auxiliary polyol may be utilized in variousamounts.

In a second embodiment of the binder component, the binder component ofthe adhesive system includes a UF resin, a phenol formaldehyde (PF)resin, or a melamine UF (MUF) resin, or a combination thereof. The PFresin may be any type in the art. Similarly, the UF resin may be anytype of UF resin or melamine UF resin in the art. Suitable grades of UFresins and melamine UF resins are commercially available from a varietyof suppliers, such as Hexion Specialty Chemicals Inc. of Springfield,Oreg. A specific example of a suitable UF resin is Casco-Resin F09RFPfrom Hexion.

In a third embodiment of the binder component, the binder component ofthe adhesive system is a soy-based adhesive. Soy-based adhesivestypically include soy flour which may or may not be modified. Thesoy-based adhesive can be in the form of a dispersion. The soy can havevarious functional groups, such as lysine, histidine, arginine,tyrosine, tryptophan, serine, and/or cysteine. Each group, if present,can range from about 1% to about 8% by weight based on the soy itself.In certain embodiments, the soy flour may be copolymerized, such as withPF, UF, pMDI, etc. Suitable soy-based adhesives are described in: Woodadhesives 2005: Nov. 2-4, 2005 . . . San Diego, Calif., USA. Madison,Wis.: Forest Products Society, 2005: ISBN: 1892529459: pages 263-269;which is incorporated by reference in its entirety in variousnon-limiting embodiments.

In certain embodiments, the soy-based adhesive includes a combination ofpolyamidoamine-epi-chlorohydrin (PAE) resin and soy adhesive. The PAEresin and soy adhesive may be used in various ratios, typically with agreater amount of soy adhesive being present relative to the amount ofPAE resin. Suitable grades of PAE and soy adhesives are commerciallyavailable from Hercules Incorporated of Wilmington, Del., such asHercules® PTV D-41080 Resin (PAE) and PTV D-40999 Soy Adhesive. In oneembodiment, the binder component includes a combination of theaforementioned PAE resin and soy adhesive.

Typically, such as in OSB, PB, scrimber, or MDF applications, the bindercomponent is utilized in an amount of from about 1 to about 25, about 1to about 20, about 1 to about 15, about 2 to about 10, about 5 to 15,about 5 to 10, or about 5 to 12, parts by weight, based on 100 parts byweight of the lignocellulosic pieces, or any subrange in between.

In certain embodiments, the isocyanate component is utilized in anamount of from about 1.4 to about 10.5, 2 to about 3, about 2.25 toabout 2.75, or about 2.5, parts by weight, based on 100 parts by weightof the lignocellulosic pieces, or any subrange in between. In anotherembodiment, the UF, PF, and/or MUF resin is utilized in an amount ofabout 5 to about 10, about 5 to about 12, or about 5 to about 15, partsby weight based on 100 parts by weight of the lignocellulosic pieces, orany subrange in between. In another embodiment, the soy-based adhesiveis utilized in an amount of about 7 to about 8 parts by weight based on100 parts by weight of the lignocellulosic pieces, or any subrange inbetween. Generally, when too little of the binder component is utilized,the resulting article does not have the necessary physical properties tobe commercially successful. Likewise, when too much of the bindercomponent is utilized, cost of manufacturing the article generallyincreases beyond any imparted benefits of utilizing such amounts of thebinder component.

The adhesive system may further include an additive component. Ifutilized, the additive component is typically chosen from partingagents, sizing agents, catalysts, fillers, flame retardants,plasticizers, stabilizers, cross-linking agents, chain-extending agents,chain-terminating agents, air releasing agents, wetting agents, surfacemodifiers, foam stabilizing agents, moisture scavengers, desiccants,viscosity reducers, reinforcing agents, dyes, pigments, colorants,anti-oxidants, compatibility agents, ultraviolet light stabilizers,thixotropic agents, anti-aging agents, lubricants, coupling agents,solvents, rheology promoters, adhesion promoters, thickeners, smokesuppressants, anti-static agents, anti-microbial agents, fungicides,insecticides, and combinations thereof. The additive component may beutilized in various amounts.

Other suitable additives include those described in U.S. Publication No.2006/0065996 to Kruesemann et al., the disclosure of which isincorporated herein by reference in its entirety in various non-limitingembodiments. The additive component may include any combination of theaforementioned additives.

In certain embodiments, the additive component includes a catalystcomponent. In one embodiment, the catalyst component includes a tincatalyst. Suitable tin catalysts include tin(II) salts of organiccarboxylic acids, e.g. tin(II) acetate, tin(II) octoate, tin(II)ethylhexanoate and tin(II) laurate. In one embodiment, theorganometallic catalyst includes dibutyltin dilaurate, which is adialkyltin(IV) salt of an organic carboxylic acid. Specific examples ofsuitable organometallic catalyst, e.g. dibutyltin dilaurates, arecommercially available from Air Products and Chemicals, Inc. ofAllentown, Pa., under the trademark DABCO®. The organometallic catalystcan also include other dialkyltin(IV) salts of organic carboxylic acids,such as dibutyltin diacetate, dibutyltin maleate and dioctyltindiacetate.

Examples of other suitable catalysts include iron(II) chloride; zincchloride; lead octoate; tris(dialkylaminoalkyl)-s-hexahydrotriazinesincluding tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine;tetraalkylammonium hydroxides including tetramethylammonium hydroxide;alkali metal hydroxides including sodium hydroxide and potassiumhydroxide; alkali metal alkoxides including sodium methoxide andpotassium isopropoxide; and alkali metal salts of long-chain fatty acidshaving from 10 to 20 carbon atoms and/or lateral OH groups.

Further examples of other suitable catalysts, specifically trimerizationcatalysts, include N,N,N-dimethylaminopropylhexahydrotriazine,potassium, potassium acetate, N,N,N-trimethyl isopropyl amine/formate,and combinations thereof. A specific example of a suitable trimerizationcatalyst is commercially available from Air Products and Chemicals, Inc.under the trademark POLYCAT®.

Yet further examples of other suitable catalysts, specifically tertiaryamine catalysts, include dimethylaminoethanol,dimethylaminoethoxyethanol, triethylamine,N,N,N′,N′-tetramethylethylenediamine, N,N-dimethylaminopropylamine,N,N,N′,N′,N″-pentamethyldipropylenetriamine,tris(dimethylaminopropyl)amine, N,N-dimethylpiperazine,tetramethylimino-bis(propylamine), dimethylbenzylamine, trimethylamine,triethanolamine, N,N-diethyl ethanolamine, N-methylpyrrolidone,N-methylmorpholine, N-ethylmorpholine, bis(2-dimethylamino-ethyl)ether,N,N-dimethylcyclohexylamine (DMCHA),N,N,N′,N′,N″-pentamethyldiethylenetriamine, 1,2-dimethylimidazole,3-(dimethylamino) propylimidazole, and combinations thereof. Specificexamples of suitable tertiary amine catalysts are commercially availablefrom Air Products and Chemicals, Inc. under the trademark POLYCAT®. Thecatalyst component can be utilized in various amounts. The catalystcomponent may include any combination of the aforementioned catalysts.

In certain embodiments, the article is substantially free of UF resinand/or PF resin. By “substantially free”, it is meant that in theseembodiments, the UF resin and/or PF resin is present in an amount nogreater than about 15, no greater than about 10, no greater than about5, or approaching or equaling 0, parts by weight, based on 100 parts byweight of the article, or any subrange in between. In other embodiments,the article is completely free of UF resin and/or PF resin.

The adhesive system also includes the compatibilizer component, suchthat the article further includes the compatibilizer component disposedon the plurality of lignocellulosic pieces. By “disposed on”, it ismeant that the compatibilizer component is in contact with at least aportion of the lignocellulosic pieces. It is to be appreciated thatvarious forms of the article can exist during manufacture, such as awet/uncured state to a dry/cured state. The “wet” form of the articlemay also be referred to as a mass, furnish, or mat; whereas the “dry”form is generally the final form of the article, such as PB, OSB, etc.It is to be appreciated that the final form of the article may have someresidual moisture content. The compatibilizer component is generallypresent during formation of the reaction product. The compatibilizercomponent may be applied onto the lignocellulosic pieces (e.g. byspraying) or may be combined with the lignocellulosic pieces (e.g. in amixer) or both. Alternatively, the compatibilizer may be sprayeddirectly on a conveyor belt or other processing apparatus either inconjunction with, or separately from, application to, or mixture with,the lignocellulosic pieces.

The compatibilizer component includes or is a trialkyl phosphate (TAP).The triakyl phosphate may have the chemical formula R₃PO₄ wherein each Ris independently an alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms.For example, the trialkyl phosphate may be trimethyl phosphate (TMP),triethyl phosphate (TEP), tripropyl phosphate (TPP), tributyl phosphate(TBP), tripentyl phosphate (TPP), trihexyl phosphate (THP), orcombinations thereof. Each R group may have the same number of carbonatoms and may be the same as one another or may be isomers of oneanother. Alternatively one or more R groups may have a different numberof carbon atoms from one another.

In certain embodiments, the compatibilizer component is TEP. TEP has thechemical formula (C₂H₅)₃PO₄ and may also be referred to as “phosphoricacid, triethyl ester”. TEP is typically classified as a polar nonionicsolvent.

In certain embodiments, it is believed that the TAP (such as TEP) actsas a phase transfer catalyst for the reactions of isocyanates (e.g. MDI,pMDI, etc.) with proton donating materials such as water, polyols and/orpolyamines. The TAP can also act as a solvent between the components,e.g. isocyanates, water, and various polyols and/or polyamines that aresoluble in the TAP. It is believed that the TAP allows the reaction tooccur at a faster rate and at lower temperatures by removing or at leastreducing phase barriers between normally immiscible liquid reactants. Anexample is in the reaction between water and MDI/pMDI to form polyurealinkages. Another example is the formation of polyurethane linkages,e.g. when one or more polyols are utilized. Such a reaction(s) can bethe rate determining step for the formation of the article. As describedfurther below, the inclusion of the TAP in the adhesive system alsoallows for shorter pressing times for the manufacture of the article byfacilitating reaction of the components of the adhesive system. Incertain embodiments utilizing the isocyanate-reactive component, e.g.the polyol, the TAP can be carried therein for ease of handling. The TAPcould be included along with other components as well, or utilizedseparate from other components of the adhesive system. In embodimentsutilizing highly viscous isocyanate resins (e.g. those that are thick,semisolid, or solid at room temperature), the TAP can be utilized toreduce viscosity, which eases handling, manufacture, etc. For example,the TAP can be blended with such resins to reduce/remove heatingrequirements, to reduce burden on pumping equipment, to promote fasterapplication, to promote faster reaction, etc. It is also thought thatthe TAP can be useful for lowering the total amount of binder componentrequired to form the article.

The compatibilizer may further include a carrier or solvent, e.g. water,in addition to the TAP. Such solvents can be used in various amounts.Typically, such as in OSB, PB, or fiberboard (e.g. MDF) applications,the compatibilizer component is utilized in an amount of at least about0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7, about 5 toabout 50, about 5 to about 10, about 5 to about 7, about 7 to about 10,about 8.5 to about 50, about 10 to about 45, about 10 to about 40, orabout 10 to about 35, parts by weight, based on 100 parts by weight ofsaid binder component, or any subrange in between. In specificembodiments, the compatibilizer is utilized in an amount of from about20 to about 50, about 22.5 to about 47.5, or about 25 to about 45, partsby weight, based on 100 parts by weight of said binder component (e.g.MDI/pMDI), or any subrange in between.

Typically, the binder component and compatibilizer component areutilized in the article in a combined amount of from about 1 to about25, about 1 to about 15, about 1 to about 10, or about 5 to about 10,parts by weight, based on 100 parts by weight of the lignocellulosicpieces, or any subrange in between. By “combined amount”, it is meantthat each of the binder component and the compatibilizer component areindividually utilized in the article in a positive amount, i.e., in anamount greater than zero (0) parts by weight based 100 parts by weightof the lignocellulosic pieces. The binder component and compatibilizercomponent can be utilized in the article in various weight ratios. Invarious embodiments, this ratio is from 0.1:1 to 1:0.1. In anotherembodiment, this ratio is about 1:1. It is to be appreciated that theother optional components, e.g. the additive component, can also beutilized to form the article. In related embodiments, the adhesivesystem is utilized in an amount of from about 1 to about 15 parts, orabout 1 to about 25 parts, by weight based on 100 parts by weight ofsaid article, or any subrange in between.

In certain embodiments, the adhesive system includes MDI and the TAP. Infurther embodiments, the adhesive system consists essentially of MDI andthe TAP. In yet further embodiments, the adhesive system consists of MDIand the TAP. In other related embodiments, the MDI is replaced in whole,or part, by pMDI. In these embodiments, water reacts with the MDI/pMDIform the reaction product. The water can be part of the pre-curedadhesive system in addition to the binder and compatibilizer components(i.e., water is purposefully added/utilized), and/or already presentalong with the lignocellulosic pieces (e.g. as moisture, it waspreviously sprayed on, etc.). In other related embodiments, the adhesivesystem further includes a polyol, e.g. a polymer polyol, in addition tothe TAP and MDI/pMDI. Other components may also be present, such as theadditive component. The TAP and the MDI/pMDI can be utilized in anyweight ratio. In various embodiments, this ratio is from 0.1:1 to 1:0.1.In another embodiment, this ratio is about 1:1.

The binder component and the compatibilizer component may be supplied toconsumers for use by various means, such as in railcars, tankers, largesized drums and containers or smaller sized drums, totes, and kits. Forexample, one drum can contain the binder component and another drum cancontain the compatibilizer component. In general, providing thecomponents to consumers separately reduces premature potential reactionof the components and provides for increased formulation flexibility forforming the adhesive. For example, a consumer can select a specificbinder component and specific compatibilizer component, and amountsthereof, to prepare the article formed therefrom. If other componentsare utilized, such as the additive component, e.g. the catalystcomponent, such components can be provided separately or premixed withone of or more of the binder component or the compatibilizer component.

In certain embodiments, the article further includes polymericparticles. In these embodiments, the polymeric particles are generallyco-mingled with the lignocellulosic pieces. The polymeric particles canbe useful for reducing weight of the article. In these embodiments, theadhesive system is generally disposed on the lignocellulosic pieces andthe polymeric particles for bonding the lignocellulosic pieces and thepolymeric particles.

If utilized, the polymeric particles can be of various sizes,distributions, shapes, and forms. Typically, the polymeric particles arein the form of beads. In certain embodiments, the polymeric particlesare expanded polystyrene beads; however, the polymeric particles can beformed from various thermoplastics and/or thermosets. Specific examplesof suitable polymeric particles are commercially available from BASFCorporation under the trademark of STYROPOR®. Other examples of suitablepolymeric particles are described in U.S. Pat. No. 8,304,069 to Schmidtet al., the disclosure of which is incorporated herein by reference inits entirety in various non-limiting embodiments.

If utilized, the polymeric particles can be utilized in an amount offrom about 1 to about 30, about 1 to about 20, or about 1 to about 10,parts by weight, based on 100 parts by weight of the lignocellulosicpieces, or any subrange in between.

The article may be of various sizes, shapes, and thickness. For example,the article can be configured to mimic conventional composite articles,such as OSB, PB, scrimber, and MDF beams, boards, or panels. The articlecan also be of various complex shapes, such as moldings, fascias,furniture, etc. In certain embodiments, the article is fiberboard, e.g.MDF. In other embodiments, the article is OSB, scrimber, or OSL. In yetother embodiments, the article is PB. The article can include one ormore layers. For example, if the article is OSB, the article can includeone layer, e.g. a core layer, two layers, e.g. a core layer and aface/fascia layer, or three or more layers, e.g. a core layer and twofascia layers.

In certain embodiments, such as for OSB applications, the article has afirst fascia layer including a first portion of the plurality oflignocellulosic pieces compressed together and substantially oriented ina first direction. The article further has a second fascia layer spacedfrom and parallel to the first fascia layer and including a secondportion of the plurality of lignocellulosic pieces compressed togetherand substantially oriented in the first direction. The article yetfurther has a core layer disposed between the first and second fascialayers and including a remaining portion of the plurality oflignocellulosic pieces compressed together and substantially oriented ina second direction different than the first direction. In theseembodiments, at least one of the portions of the plurality oflignocellulosic pieces is compressed together with the adhesive system.The fascia layers can also include the adhesive system in addition to,or alternate to, the core layer. In certain embodiments, the core layerincludes the polymeric particles along with the lignocellulosic pieces.The layers can each includes different adhesive systems, depending onthe specific components utilized in the respective adhesive systems ofthe layers. In certain embodiments, at least one of the layers, e.g. oneor both of the fascia layers, can include PF resin. Each of the layerscan be of various thicknesses, such as those encountered withconventional OSB layers. OSL typically has lignocellulosic piecessubstantially orientated in only one direction. Other types of compositearticles, e.g. wood composites, and their methods of manufacture, thatcan be formed, e.g. by utilizing the adhesive system, are described bypages 395 through 408 of THE POLYURETHANES HANDBOOK (David Randall &Steve Lee eds., John Wiley & Sons, Ltd. 2002), which is incorporatedherein by reference in their entirety in various non-limitingembodiments.

The article has an original thickness, i.e., a thickness aftermanufacture, e.g. after pressing the mat to form the final, i.e., cured,article. Typically, due to the adhesive system, the article exhibits aswelling of less than about 10%, less than about 5%, or less than about3%, based on a 24-hour cold-soak test according to ASTM D1037. Thethickness can vary, but is typically of from about 0.25 to about 10,about 0.25 to about 5, or about 0.25 to about 1.5, inches, or anysubrange in between. It is to be appreciated that describing thicknessesmay not be suitable when describing complex shapes other than boards orpanels. As such, the article can be of various dimensions based on finalconfiguration of the article.

The article has an internal bond (IB) strength. Typically, the IBstrength is greater than about 20, greater than about 30, greater thanabout 40, greater than about 50, greater than about 60, greater thanabout 70, greater than about 80, greater than about 90, or greater thanabout 100, pounds per square inch (psi), according to ASTM D1037. Incertain embodiments, the article has an IB strength of from about 50 toabout 500, about 100 to about 300, or about 150 to about 250, psi,according to ASTM D1037, or any subrange in between.

IB strength is a tensile property. Typically, in conventional articles,as IB strength increases, flexural properties such as modulus ofelasticity (MOE) and modulus of rupture (MOR) change, specifically, MOEgenerally decreases as IB strength increases.

Typically, the article has a MOE greater than 75,000, greater than95,000, greater than 100,000, or greater than 110,000, psi, according toASTM D1037. Typically, the article has a MOR greater than 3,000, greaterthan 3,250, greater than 3,300, or greater than 3,500, psi, according toASTM D1037.

Also disclosed is a method of forming the article. To form the article,the lignocellulosic pieces are generally provided. The lignocellulosicpieces can be derived from a variety of lignocellulosic sources, and canbe formed from a variety of processes.

The binder component and the compatibilizer component, and typicallyother components, e.g. the isocyanate-reactive and/or additivecomponent(s), (all of which are hereinafter referred to simply as “thecomponents”) are applied to the plurality of lignocellulosic pieces toform a mass. The components can be applied to the lignocellulosic piecesat the same time, or can be applied to the lignocellulosic pieces atdifferent times. In one embodiment, the binder component is applied thelignocellulosic pieces prior to the compatibilizer component. In anotherembodiment, the binder component is applied to the lignocellulosicpieces after the compatibilizer component. In yet another embodiment,the binder component and the compatibilizer component are appliedsimultaneously to the lignocellulosic pieces. For example, the bindercomponent can be applied to the lignocellulosic pieces, and then thecompatibilizer component can be applied to the lignocellulosic pieces atsome time later, or vice versa. Alternatively, the components can beapplied at the same time, either separately, and/or premixed. In oneembodiment, the components are blended to form the adhesive system, suchthat the adhesive system is applied to the lignocellulosic pieces. Thecomponents can be applied to the lignocellulosic pieces by variousmethods, such as by mixing, tumbling, rolling, spraying, sheeting,blow-line resination, blending (e.g. blow-line blending), etc. Forexample, the components and the lignocellulosic pieces can be mixed ormilled together during the formation of the mass, also referred to as abinder-lignocellulosic mixture or “furnish”, as further described below.

Typically, the components are applied to the lignocellulosic pieces by aspraying, an atomizing or a fogging process. The plurality oflignocellulosic pieces having the binder component and thecompatibilizer component applied thereon are then disposed on a carrier,and generally form (or define) the mass. The mass can then be formedinto mat, such as by dropping the mass onto a carrier, e.g. a conveyorbelt, or, alternatively, the mat can be formed directly on the carrier,i.e., the binder-lignocellulosic mixture is formed directly on thecarrier. In other words, the plurality of lignocellulosic pieces havingthe binder component and the compatibilizer component applied thereoncan be arranged on the carrier to form the mass in various ways. Themass can then be fed to a former, which generally forms the mass into amat having a predetermined width and a predetermined thickness with theplurality of lignocellulosic pieces loosely oriented on the carrier. Thepredetermined width and thickness of the mat are determined according tofinal widths and thicknesses desired for the article, as describedfurther below. The mat can then be formed in various shapes, such asboards or panels, or formed into more complex shapes such as by moldingor extruding the mat to form the article.

In certain embodiments, the components are sprayed, atomized, and/orfogged onto the lignocellulosic pieces while the lignocellulosic piecesare being agitated in suitable equipment. Spraying, atomizing andfogging can occur via use of nozzles, such as one nozzle for eachindividual component supplied thereto, or nozzles that have two or morecomponents premixed and supplied thereto. Generally, at least one nozzleapplies the binder component and at least one nozzle applies thecompatibilizer component. To maximize coverage of the lignocellulosicpieces, the components are generally applied by spraying droplets oratomizing or fogging particles of the components onto thelignocellulosic pieces as the lignocellulosic pieces are being tumbledin a rotary blender or similar apparatus. As another example, thelignocellulosic pieces can be coated with the components in a rotarydrum blender equipped with at least one, typically at least two or threespinning disk atomizers. Tumblers, drums, or rollers including bafflescan also be used. It is believed that applying shear to the componentsis important, especially if such components have high viscosities. Shearforce can be useful for obtaining proper distribution of the componentswith respect to the lignocellulosic pieces, and can be obtained byspecific nozzle design to obtain proper atomization of the components.It is believed that the components should be mixed very well, be itbefore or after application to the lignocellulosic pieces. Of coursecomplete coverage of the lignocellulosic pieces with the components isdesirable to ensure proper bonding. Atomization is useful for maximizingdistribution of the components onto the lignocellulosic pieces, based inpart on droplet size distribution of the components. Typically, thecomponents are not premixed prior to application, to prevent prematurereaction. As such, the components are each individually applied onto thelignocellulosic pieces via one or more nozzles, typically, by one nozzleper component to prevent premature reaction and/or contamination.

Alternatively, the lignocellulosic pieces can be provided directly tothe carrier, and the components can be applied to the lignocellulosicpieces, e.g. by spraying or sheeting, to form the mass. For example, thelignocellulosic pieces can be disposed on a conveyor belt or a plate,and then sprayed with the components to form the mass. Further, at leastone of the components, e.g. the compatibilizer component, can already bepresent on the lignocellulosic pieces, such that the remainingcomponent(s) of the adhesive system, e.g. the binder component, can thenbe applied to the lignocellulosic pieces and to the compatibilizercomponent to form the mass.

The amount of the components to be applied and mixed with thelignocellulosic pieces is dependant upon several variables including,the specific components utilized, the size, moisture content and type oflignocellulosic pieces used, the intended use of the article, and thedesired properties of the article. The resulting mass is typicallyformed into a single or multi-layered mat that is compressed into, forexample, OSB, PB, scrimber, MDF, or another article of the desired shapeand dimensions. The mass can also be formed into more complex shapes,such as by molding or extruding the mass.

The mat can be formed in any suitable manner. For example, the mass canbe deposited on a plate-like carriage carried on an endless belt orconveyor from one or more hoppers spaced above the belt. When amulti-layer mat is formed, a plurality of hoppers are used with eachhaving a dispensing or forming head extending across the width of thecarriage for successively depositing a separate layer of themass/furnish as the carriage is moved between the forming heads. The matthickness will vary depending upon such factors as the size and shape ofthe lignocellulosic pieces, the particular technique used in forming themat, the desired thickness and density of the final article and thepressure used during the press cycle. The thickness of the mat isusually about 5 times to about 20 times a final thickness of thearticle. For example, for flakeboard or particleboard panels of 0.5 inchthickness and a final density of about 35 lbs/ft³, the mat usually willoriginally be about 3 inches to about 6 inches thick. The width of themat is usually substantially the same as a final width of the article;however, depending on configuration of the article, the final width maybe a fraction of the thickness, similar to description of the thickness.

Typically, the lignocellulosic pieces are loosely oriented in the massand mat. A carrier is provided, such as a conveyor belt or plate, andthe mass and eventual mat is disposed on the carrier. The mass caneither be formed directly on the carrier, and/or transferred to thecarrier, after forming, e.g. in a tumbler. It is thought that theadhesive system substantially maintains orientation of the plurality oflignocellulosic pieces in the mass while on the carrier. For theadhesive system to maintain orientation of the lignocellulosic piecesthere is no requirement that the orientation is maintained perfectly.For example, minor distortion may occur. In general, the adhesive systemserves as a “tackifier” or as “sticky” glue, and can be used as asubstitute or supplemental adhesive for UF resins and/or PF resins, aswell as for other conventional adhesives. As such, the adhesive systemhas tack or cold-tack. Cold-tack can be determined in a variety of ways.For example, one can use a “slump” test, which employs a funnel packedfull of the mass, the funnel is then tipped onto a surface and removed,such that the mass (in the shape of the funnel) remains on the surface.The funnel shaped mass can then be observed for changes in shape overtime, such as changes in angle due to slumping/collapsing of the funnelshaped mass. Another example is referred to as a “snowball” test, whereone can grab a handful of the mass, make a ball of the mass in hand, andtoss the ball up and down to determine if the ball falls apart. Othersuitable tests are described in ASTM D1037.

When the mass is formed into the mat, the adhesive system alsosubstantially maintains the width and the thickness of the mat while themat is on the carrier. As can be appreciated, when the carrier moves,such as by conveying, the adhesive system keeps the mat from fallingapart due to vibrations. Vibrations can also occur, for example, if thecarrier is a plate, and the plate is being moved to a press. Suchvibrations can cause orientation problems with the lignocellulosicpieces, can cause reduced internal bond (IB) strength, and can causeother similar issues.

The article is typically formed from the mat by compressing the matformed from the mass at an elevated temperature and under pressure.Typically, at least pressure is applied to the mat for an amount of timesufficient to form the article. Heat is also typically applied. Suchconditions facilitate reaction of the adhesive system, specially, atleast reaction of the binder component, to form the reaction product. Byimparting tack, the adhesive system can reduce movement of thelignocellulosic pieces in the mat, such as by reducing a chance that thelignocellulosic pieces will blow apart when applying pressure to themat. Specifically, speed of applying pressure to the mat to form thearticle can be increased relative to conventional pressing speed and/orpressures utilized to form conventional composite articles, whichprovides economic benefits, such as increased throughput, formanufacturers of the article. The same tack imparted by the adhesivesystem is useful during movement of the mat, such as when beingconveyed.

Typically, heat is applied to the mat to facilitate cure of the adhesivesystem. Press temperatures, pressures and times vary widely dependingupon the shape, thickness and the desired density of the article, thesize and type of lignocellulosic pieces, e.g. wood flakes or sawdust,the moisture content of the lignocellulosic pieces, and the specificcomponents utilized. The press temperature, for example, can range fromabout 100° C. to about 300° C. To minimize generation of internal steamand the reduction of the moisture content of the final composite articlebelow a desired level, the press temperature is typically less thanabout 250° C. and most typically from about 180° C. to about 240° C., orany subrange in between. The pressure utilized is generally from about300 to about 800 pounds per square inch (psi), or any subrange inbetween. Typically, the press time is from 120 to 900 seconds, or anysubrange in between. The press time utilized should be of sufficientduration to at least substantially cure the adhesive (in order tosubstantially form the reaction product) and to provide a compositearticle of the desired shape, dimension and strength. For themanufacture of, e.g. flakeboard or PB panels, the press time dependsprimarily upon the panel thickness of the composite article produced.For example, the press time is generally from about 200 seconds to about300 seconds for a composite article with about a 0.5 inch thickness. Itis contemplated that pressure may be utilized without any external heatadded in any of the aforementioned steps. Alternatively, external heatmay be utilized without any external pressure used in any of theaforementioned steps. Moreover, both external heat and pressure may beapplied in any of the aforementioned steps.

Other suitable methods for forming the article, are described in theU.S. Pat. No. 6,451,101 to Mente et al.; U.S. Pat. No. 6,458,238 toMente et al.; U.S. Pat. No. 6,464,820 to Mente et al.; U.S. Pat. No.6,638,459 to Mente et al.; U.S. Pat. No. 6,649,098 to Mente et al., U.S.Pat. No. 6,344,165 to Coleman; U.S. Pat. No. 7,439,280 to Lu et al.; andU.S. Pat. No. 8,486,523 to Mente; and U.S. Publication No. 2005/0242459to Savino et al., each of which is expressly incorporated herein invarious non-limiting embodiments.

Without being bound or limited to any particular theory, it is thoughtthat presence of the compatibilizer component reduces the amount of timerequired to form the article relative to the amount of time requiredwhen the compatibilizer component is not utilized to form the article.Specifically, it is thought that the compatibilizer component is usefulfor reducing cure time of the adhesive system during manufacture of thearticle. As such, throughput of the articles can be increased viaincreased manufacturing speeds, e.g. press speeds (i.e., shorterpressing times). Other manufacturing benefits can also be realized, suchas improved application of the components of the adhesive system to theplurality of lignocellulosic pieces relative to conventional adhesives.In addition, it is believed that the articles include excellent physicalproperties. For example, in certain embodiments, the articles can haveone or more of the following: increased bond strength, reduced edgeswelling, improved release properties, improved flexural modulus, and/orreduced emissions, each relative to conventional articles. It is thoughtthat other potential advantages afforded by the use of thecompatibilizer component are: improved plasticization of thelignocellulosic pieces; reduced binder component viscosity leading toimproved distribution on the lignocellulosic pieces; and improved flametest performance of the articles. It is thought that the compatibilizercomponent can also improve the performance of other, optional,components utilized to form the articles, such as polyols through phasetransfer catalysis and/or viscosity reducing mechanisms.

In various embodiments, use of the compatibilizer component may increaseprocessing speeds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, percent ormore. The increase in processing speed may be achieved with minimal, ifany, increase in destructive forces applied to the developing articleduring formation. Alternatively, use of the compatibilizer component maydecrease the destructive forces applied to the developing article.

In other embodiments, the compatibilizer component may decrease theviscosity and/or surface tension of one or more release agents and/orsoaps/detergents. This interaction is typically a physical interactionand not necessarily a chemical interaction. For example, thecompatibilizer component may decrease the viscosity and/or surfacetension of a silicone surfactant, including any of those describedabove. This decrease in surface tension may improve coverage of therelease agents and/or soaps/detergents per unit weight. This decreasemay be quantified via surface tension measurements made with agoniometer.

More specifically, contact angle data can be taken in a temperaturecontrolled room maintained at 20° C. The goniometer can be the Kruss DSAModel 100 Drop Shape Analysis System. For example, 5 microliter dropletscan be deposited on a clean substrate stage plate by the goniometers'sautomated dosing syringe. Measurements of the contact angle can then beautomatically recorded approximately every tenth of a second up to 12seconds (i.e., 120 tenths of seconds). The left and right contact anglescan be recorded and averaged by the goniometer's software.

In various embodiments, release agent enhancement can be observed. TheTAP may form a coating upon a metal belt or platen in a production lineand may help the release agent and/or soap/detergents remain on thesurface of the metal belt or platen. This may reduce destructive forcesapplied by press operation (and/or during exit of a continuous press) toan article. This effect may last for several minutes or hours even aftercessation of application of the release agent and/or soap/detergents tothe metal belt or platen, or even after general use of the release agentand/or soap/detergents in the article itself. In other words, even afterthe release agent and/or soap/detergents is no longer used in a processdescribed herein or in the article described herein, the benefits maysurprisingly remain. Referring back to the aforementioned increase inprocessing speed, this increase may be observed even after the removalof the TAP from the process. For example, even after a source of TAP isremoved from the process of forming the article, the increase inprocessing speed may still be observed. Without intending to be bound byany particular theory, this may occur because some of the TAP may stillbe present on one or more pieces of the processing machinery orapparatus, e.g. a conveyor belt, platen, wheel, etc. This effect may beobserved 1, 2, 3, 4, 5, 6, 7, 8 or more hours after the source of theTAP is removed.

The TAP may be added directly to the release agent and/or soap/detergentand may not be included in the article at all. Alternatively, the TAPmay be added to both the release agent and/or soap/detergent and also beused in the article. Even further, the TAP may be used in the articleand not added to the release agent and/or soap/detergent at all. The TAPmay be utilized in any one or more portions or components of the articleand/or in any one or more portions or steps of the process or methoddescribed herein.

It is also contemplated that the TAP may be added to the release agent(e.g. a silicone surfactant) and/or soap/detergent independently of anyarticle and independently of any method or process used to form thearticle described herein. Said differently, this disclosure alsoprovides an independent mixture of the TAP and the release agent and/orsoap/detergent that is used for purposes not expressly described herein.

The following examples, illustrating the articles, are intended toillustrate and not to limit the disclosure.

Examples

Comparative articles (Example 1) and disclosure articles (Examples 2, 3,and 4) are prepared. The articles are particleboards. The articles aremade using typical production methods for manufacturing particleboard(PB), such that method of manufacture does not impart differencesbetween the articles. The amount and type of each component used to formfurnishes of the articles are illustrated in Table I below.

TABLE I Example No. Component 1 2 3 4 Lignocellulosic Pieces 32,65932,659 32,659 32,659 (g) Lignocellulosic Pieces 94.44 93.89 93.89 93.36(wt. %) Binder (g) 824 824 824 824 Binder (wt. %*) 2.52 2.52 2.52 2.52Compatibilizer (g) 0 200 200 400 Compatibilizer 0.00 0.61 0.61 1.22 (wt.%*) Water (g) 1100 1100 1100 1100 Water (wt. %*) 3.37 3.37 3.37 3.37Moisture Content 9.03 & 8.21 8.38 8.43 9.20 (wt. %) *Each based on 100parts by weight of the lignocellulosic pieces

The lignocellulosic pieces are of shape and size typically used to formPB. Specifically, the lignocellulosic pieces include pine having a dryweight content of about 88% and a moisture content of about 7%, byweight, passed on 100 parts by weight of the lignocellulosic pieces.

The binder is an isocyanate including MDI and pMDI (referred to simplyas “MDI” below). The isocyanate has a functionality of about 2.7, NCOcontent of about 31.5 wt. %, and viscosity of about 200 cps at 25° C.The isocyanate is commercially available from BASF Corporation.

The compatibilizer used in Examples 1-4 is TEP. The compatibilizerutilized in Examples 2 and 4 is 100% TEP, the compatibilizer in Example3 is a blend of 200 grams water and 200 grams TEP. These amounts areaccounted for as total amounts in Table I above. TEP is commerciallyavailable from a variety of sources.

Each furnish is formed by spraying and blending the components in ablender. Order of addition to the blender is as follows: lignocellulosicpieces, water, binder, and compatibilizer. Example 3 utilizes a blend ofwater and TEP as the compatibilizer (such that these are pre-mixed priorto adding to the blender). The only difference between Example 2 and 3is the order of addition of components, with Example 3 utilizing apre-blend of a portion of the total amount water and an entirety of thetotal amount TEP. Each furnish is made at ambient temperature.

After formation, each furnish is split evenly into six masses (or mats)that weigh ˜4,800 grams each. The mats are compressed using a standardPB forming apparatus under typical temperature and pressure conditionsused in the art, thereby forming each of the respective articles. Thearticles (i.e., particleboards) are ˜1″ thick, ˜20″ wide, and ˜20″ long.Different press times are utilized to form each of the articles, asillustrated in Table II below. After the articles are formed, eacharticle is visually inspected for delamination or other defects.Internal bond (IB) strength of the articles is determined according toASTM D1037. Final moisture content of the articles is determined using aheat balance and is shown in Table I above.

To determine analyze IB strength, the particles boards are cut in half.Next, a 2″ strip is cut from one of the halves. That strip is then cutinto eight 2″ strips which are tested for IB. It is thought that edgeeffects (e.g. squeeze out) resulting from lab scale board size plays afactor in the ultimate IB values of the strips. For example, two orthree of the eight strips can have lower values than the remaining ofthe eight strips. It is believed that this is often caused by squeezeout at the edges.

TABLE II Press Time and Formulation Effects on IB (psi) of Single LayerParticle Board Panels Press MDI MDI 2.5%; MDI 2.5%; MDI 2.5%; Time (sec)2.5% TEP 0.6% (1) TEP 0.6% (2) TEP 1.2% 270 103 247 90 243 109 228 60112 84 133 220 53 75 218 79 215 79 68 123 214 36 213 79.59 (3) 210 43 53116 200 55 198 36 195 27 190 28 (1) Added neat; (2) mixed in water,overal moisture content unchanged; (3) density variation.

While some of the articles show some marginal defects or delaminationupon visual inspection, none of the disclosure articles have completedelamination (which would be represented, e.g., by a fissure all the waythrough the article). Overall, the disclosure articles require lesspress time than the comparative articles. Additional properties andresults of the various articles can be appreciated with reference toFIGS. 1 through 5.

First Set of Additional Examples

A first set of additional examples models addition of a TAP and watersolution (or mixture) to pMDI. The water and phosphate blend typicallyhas to dissolve the pMDI to speed the reaction thereof.

More specifically, 1.5 grams of each of four TAPs was added to 20 gramsof water in open beakers to form four independent mixtures. Trimethylphosphate (TMP) and triethyl phosphate (TEP) dissolved completely. Thetripropyl phosphate (TPP) partially dissolved while very little of the(TBP) dissolved. After stirring to maximize dissolution, 2.0 grams ofpMDI (Lupranate M20FB) was added to each of the aforementioned mixtures.

None of the mixtures was clear. The tripropyl phosphate (TPP) formedsolid pMDI urea most rapidly. The tributyl phosphate (TBP) blend was thesecond fastest, while the methyl and ethyl phosphates appeared to reactsimilarly and were still liquid after 4 hours. Accordingly, this firstset of additional examples demonstrates that TPP accelerates the waterand pMDI reaction to a greater degree that the other TAPs.

Second Set of Additional Examples

A second set of additional examples models addition of pMDI as aseparate stream to a wood furnish during blending.

More specifically, 1.5 grams of each of four TAPs was added to 5.0 gramsof pMDI to form four independent mixtures. All the TAPs dissolved in thepMDI with a minimum of stirring. Then, 10 grams of distilled water wereadded to each of the mixtures and the mixtures were stirred for about 20seconds.

None of the four mixtures was clear. The mixture including trimethylphosphate (TMP) reacted the fastest. The remainder of the mixturesreacted in the following order relative to speed: triethyl phosphate(TEP), tripropyl phosphate (TPP), and tributyl phosphate (TBP).

The rate of reaction between the water and the pMDI may be determined bythe solubility of one of the two reactants in the solution/blend of thecompatibilizer and the remaining reactant. The presence of a TAP ineither water or the isocyanate increased the reaction rate over amixture of water and pMDI without catalyst.

Relative to the addition of the pMDI to the TAP, the tripropyl andtributyl phosphates were only partially soluble in water at the ratesadded. Regardless, each was a suitable solvent for pMDI such that ureaformation occurred faster than in the mixtures wherein the trimethyl andtriethyl phosphates are completely miscible.

Third Set of Additional Examples

A third set of additional examples demonstrates the effect of TEP on thesurface tension of a silicone surfactant. More specifically, the surfacetension of droplets of three samples was evaluated on stainless steel,steel, and aluminum surfaces.

The first sample is deionized water.

The second sample is a solution of 2% by weight in deionized water ofGorapur OS 1701W silicone surfactant that is commercially available fromEvonik.

The third sample is a solution of 2% by weight of the aforementionedsilicone surfactant and 2% by weight of TEP, in deionized water.

Droplets of each sample were placed on the various surfaces andevaluated to determine water contact angle in one tenth of a secondincrements from 0 to 12 seconds (i.e., 120 tenths of seconds), pursuantto the method described above using the Kruss DSA Model 100 Drop ShapeAnalysis System. The results of these evaluations are set forth in FIG.6A (stainless steel for first, second and third samples), 7A (steel forfirst, second and third samples), and 8A (aluminum for first, second andthird samples).

Moreover, photographs of various droplets for each sample are set forthas FIGS. 6B-6D (stainless steel for first, second and third samples),FIGS. 7B-7D (steel for first, second and third samples), and FIGS. 8B-8D(aluminum for first, second and third samples).

These evaluations clearly show that the inclusion of the TEP decreasesthe water contact angle of the droplets. The decreased contact angle ofthe droplet suggests that the droplets that include the TEP will exhibitbetter wetting on various surfaces which will reduce friction anddestructive forces acting on the lignocellulosic composite articleduring formation, e.g. using the process or method described herein.

An increased pMDI/water reaction rate (e.g. increased panel productionrate) was also discovered using a conventional single opening (batchprocess) laboratory press. The production speed increase attributable tosynergy with the release agent was observed on a commercial trial on acontinuous press when the speed increase continued for up to 6 hoursafter the TEP addition was stopped.

It is to be understood that the appended claims are not limited toexpress and particular compounds, compositions, or methods described inthe detailed description, which may vary between particular embodimentswhich fall within the scope of the appended claims. With respect to anyMarkush groups relied upon herein for describing particular features oraspects of various embodiments, it is to be appreciated that different,special, and/or unexpected results may be obtained from each member ofthe respective Markush group independent from all other Markush members.Each member of a Markush group may be relied upon individually and or incombination and provides adequate support for specific embodimentswithin the scope of the appended claims.

It is also to be understood that any ranges and subranges relied upon indescribing various embodiments of the present disclosure independentlyand collectively fall within the scope of the appended claims, and areunderstood to describe and contemplate all ranges including whole and/orfractional values therein, even if such values are not expressly writtenherein. One of skill in the art readily recognizes that the enumeratedranges and subranges sufficiently describe and enable variousembodiments of the present disclosure, and such ranges and subranges maybe further delineated into relevant halves, thirds, quarters, fifths,and so on. As just one example, a range “of from 0.1 to 0.9” may befurther delineated into a lower third, i.e., from 0.1 to 0.3, a middlethird, i.e., from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9,which individually and collectively are within the scope of the appendedclaims, and may be relied upon individually and/or collectively andprovide adequate support for specific embodiments within the scope ofthe appended claims. In addition, with respect to the language whichdefines or modifies a range, such as “at least,” “greater than,” “lessthan,” “no more than,” and the like, it is to be understood that suchlanguage includes subranges and/or an upper or lower limit. As anotherexample, a range of “at least 10” inherently includes a subrange of fromat least 10 to 35, a subrange of from at least 10 to 25, a subrange offrom 25 to 35, and so on, and each subrange may be relied uponindividually and/or collectively and provides adequate support forspecific embodiments within the scope of the appended claims. Finally,an individual number within a disclosed range may be relied upon andprovides adequate support for specific embodiments within the scope ofthe appended claims. For example, a range “of from 1 to 9” includesvarious individual integers, such as 3, as well as individual numbersincluding a decimal point (or fraction), such as 4.1, which may berelied upon and provide adequate support for specific embodiments withinthe scope of the appended claims.

The present disclosure has been described herein in an illustrativemanner, and it is to be understood that the terminology which has beenused is intended to be in the nature of words of description rather thanof limitation. Many modifications and variations of the presentdisclosure are possible in light of the above teachings. The presentdisclosure may be practiced otherwise than as specifically describedwithin the scope of the appended claims. The subject matter of allcombinations of independent and dependent claims, both single andmultiple dependent, is herein expressly contemplated.

1. A lignocellulosic composite article comprising: a plurality oflignocellulosic pieces derived from wood; and an adhesive systemdisposed on said plurality of lignocellulosic pieces for bonding saidplurality of lignocellulosic pieces; wherein said adhesive systemcomprises; a binder component present in an amount of from 2 to 10 partsby weight per 100 parts by weight of said lignocellulosic pieces, and acompatibilizer component comprising trialkyl phosphate and utilized inan amount of at least about 0.5 parts by weight based on 100 parts byweight of said binder component.
 2. The article of claim 1 wherein saidcompatibilizer component is triethyl phosphate (TEP).
 3. The article ofclaim 1 wherein said compatibilizer component is chosen from trimethylphosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate,and combinations thereof.
 4. The article of claim 1 wherein saidcompatibilizer component is utilized in an amount of from about 0.5 toabout 50 parts by weight based on 100 parts by weight of said bindercomponent.
 5. The article of claim 1 wherein said compatibilizercomponent is utilized in an amount of from about 0.5 to about 35 partsby weight based on 100 parts by weight of said binder component.
 6. Thearticle of claim 1 wherein said binder component is an isocyanatecomponent.
 7. The article of claim 6 wherein said isocyanate componentis chosen from diphenylmethane diisocyanates (MDIs), polymericdiphenylmethane diisocyanates (pMDIs), and combinations thereof. 8.(canceled)
 9. The article of claim 6, wherein said adhesive systemfurther comprises an isocyanate-reactive component.
 10. The article ofclaim 9 wherein said isocyanate-reactive component is chosen from water,polyols, polyamines, and combinations thereof.
 11. The article of claim9 wherein said isocyanate-reactive component comprises a polymer polyolhaving a continuous phase comprising a polyol and a discontinuous phasecomprising polymeric particles.
 12. The article of claim 11 wherein saidpolymeric particles comprise styrene acrylonitrile (SAN) copolymers. 13.The article of claim 11 or 12 wherein said polymeric particles arepresent in said polymer polyol in an amount of from about 5 to about 70parts by weight based on 100 parts by weight of said polymer polyol. 14.The article of claim 11 wherein said continuous phase comprises ahydrophobic polyol.
 15. The article of claim 1 wherein said plurality oflignocellulosic pieces are utilized in an amount of from about 75 toabout 99 parts by weight based on 100 parts by weight of said article.16. The article of claim 1 wherein said adhesive system is utilized inan amount of from about 1 to about 25 parts by weight based on 100 partsby weight of said article.
 17. The article of claim 1 wherein saidarticle is: i) oriented strand board (OSB); ii) particleboard (PB); oriii) fiberboard.
 18. A method of forming the article of claim 1, saidmethod comprising the steps of: applying the binder component and thecompatibilizer component to the plurality of lignocellulosic pieces;disposing the plurality of lignocellulosic pieces having the bindercomponent and the compatibilizer component applied thereon on a carrierto form a mass; and applying pressure and/or heat to the mass for anamount of time to form the article; wherein the compatibilizer componentreduces the amount of time required to form the article relative to theamount of time required when the compatibilizer component is not presentduring formation of the article.
 19. The method of claim 18 wherein thebinder component comprises an isocyanate component and furthercomprising the step of applying an isocyanate-reactive component to theplurality of lignocellulosic pieces.
 20. The method of claim 18 whereinthe compatibilizer component is triethyl phosphate (TEP).